Market segmentation has led to the need to produce milk with different characteristics, such as milk low in lactose, milk for infants with protein and high calcium.
Although there is the idea that milk is the liquid extracted from the udders of mammals, since this product is the raw material for the production of products covered by this description, you can name milk to these products, given that not have any foreign component.
In milk low in lactose, there are processes using the lactase and rest in the milk the monosaccharides glucose and galactose, which form the disaccharide lactose. Being the galactose sweeter than lactose, these processes can result in milk with a pronounced sweetness.
In U.S. Pat. No. 5,334,399 is disclosed a solution to this situation and is to add potassium chloride to the product where the enzymatic hydrolysis was performed. This solution is practical, but often is not allowed for the breach of official standards in some countries.
As one of these processes we have the ones who using membranes (filters) of different size (pore size) to have different filtration processes, including ultrafiltration. Depending on the pore size, filtration becomes more selective in the following order of processes called:                1. Microfiltration.—Used to retain particles of the size of bacterias and spores. Let pass proteins, fat globules, sugars, amino acids, minerals and water.        2. Ultrafiltration. Used for retaining particles of the size of protein and fat globules. Let pass sugars, amino acids, minerals and water.        3. Nanofiltration. Used for retaining particles of the size of sugars such as sucrose or table sugar. Let pass minerals and water.        4. Reverse Osmosis. Let pass almost exclusively water together with very simple minerals.        
With this knowledge, it is not possible yet to determine a milk treatment process to obtain milk with lactose-free with similar organoleptic characteristics to the ultra-pasteurized milk without desugared process.
That is, for example, a process is currently known which has the following series of steps:
The equipment used are of Membrane, which are capable of doing microfiltration processes, ultrafiltration, nanofiltration and reverse osmosis of fractionation of the various components in this case of milk.
The general process for producing lactose-free milk or low-lactose is:                Submit a low-fat or skim milk to the ultrafiltration process for obtaining the respective retentate and permeate.        The UF permeate it is submitted to the nanofiltration process similarly for obteing in the same way the respective retentate and permeate.        Is performed a mixed to the UF retentate and NF permeate.        
With these two processes, UF and NF can perform a partial or nearly complete elimination of the lactose content, where part of the minerals are also lost. This mixture is subjected then to a process of enzymatic hydrolysis with enzyme β-galactosidase to finish to reduce the lactose content generating the glucose and galactose.
You can also perform reconstitution of milk using only the UF retentate with the addition of water to the desired level of protein or include the reverse osmosis processes for concentrating minerals of the NF permeate and be used in the reconstructing milk. This process results in a milk with organoleptic strange features for a normal milk and this process does not take this into account this situation, as well as the possibility of using unit operations that makes more expensive the production process.
Indeed, an invention that shows that the steps (micro, ultra and nanofiltration and reverse osmosis) are essential to achieve a process of desugared that achieves obtaining a lactose-free milk with a sensory profile equivalent to that of a normal pasteurized milk (with lactose), with a partial removal of lactose by physical means in a first stage and subsequent removal of the remaining lactose to the use of the enzyme lactase (β-galactosidase) and the obtaining a complete lactose as a byproduct, it will be contributing knowledge non existing in the state of the art and this will deserve a patent for be protected.
The patent document CA2701066 of the inventor Vernazza, Francesco, discloses a method to obtain milk with low sugar starting from milk, and comprising at least two steps: a first step in which the milk is subjected to ultrafiltration so that produce, at the outlet, a permeate ultrafiltration and ultrafiltration retentate; and a second step in which the permeate of ultrafiltration is subjected to a nanofiltration operation so as to produce at the output a nanofiltration permeate and a nanofiltration concentrate. The nanofiltration permeate is continuously recycled directly to the nanofiltration operation, in order to dilute the retentate of the ultrafiltration and get down milk sugars starting from the latter. In this method does not take into account the physicochemical conditions to achieve a milk with organoleptic characteristics.
The Mexican patent document PA/a/2004/011243, of Janne-SAHLSTEIN discloses a method for producing lactose-free milk. The process of the invention is characterized by the steps of subjecting a product of milk to ultrafiltration (UF), nanofiltration (NF) and concentration by reverse osmosis, followed by the addition of salt to the retentate of UF. The drawback of this method is the inclusion of a step of adding salt to the retentate of ultrafiltration step and the additional step of concentration by reverse osmosis makes more expensive the method.
In the Mexican patent document PA/a/2005/002049 a consistent method disclosed in the separation of milk components, comprising the steps of:
Make pass the milk through a filtration machine in a flow of just one direction; ultrafiltration of milk in a first stage filtration using ultrafiltration means to produce a first liquid filtrate and a first concentrate, wherein the lactose content of the first filtrate is not more than 5.5% by weight; nanofiltration of the first liquid filtrate in the second filtration step using nanofiltration means to produce a second liquid filtrate and a second concentrate, wherein the lactose content of the second filtered is no more than 0.15% by weight; reverse osmosis of the second liquid filtrate in a third stage of filtration using reverse osmosis means to produce a third liquid filtrate and a third concentrate, wherein the lactose content of the third concentrate is not more than 0.06% by weight; and wherein the first filter, second filter and third filter are removed from the filter apparatus through a first outlet, a second output and a third output respectively. Again we have in the document the emergence of a reverse osmosis step.
In U.S. Pat. No. 8,445,052 (Hoist et al) describes a process for producing substantially free or lactose-free milk, preferably without the addition of water, and the product obtained by the process. The process comprises the steps of: a) ultrafiltration of the original milk to obtain a first permeate and a first retentate; b) nanofiltration of said first permeate to obtain a second permeate and a second retentate; mixing the first retentate with the second permeate to obtain a mixture; and d) hydrolyzing the lactose remaining in said mixture to obtain a hydrolyzed milk. The process results in a lactose-free product with the flavor of the original milk. The disadvantage of this process is that it does not take into account the characteristics of the original milk regarding to the composition of fats, proteins and carbohydrates.
Punctuating, the processes of the prior art have the following disadvantages: or only employ stage UF and mixed the retentate with softened water directly to reach the levels of fat and protein desired, doing with this, that these levels will generally be higher to obtain products with good sensory profile.
Or consists in a complicated process and thus higher cost of operation to use 3 stage filtration; UF, NF and inverse osmosis.
Or could to add flavor achieving a product, that according to Mexican regulation no longer be called milk and would have to be referred to as flavored milk.
With the development of research requirements in food, has been detected, in addition to the need for low milk lactose, the needs of milk high in calcium and protein and the taste of a certain sector of the population by low milks sweetness. Features of milks so far undeveloped.
And although some products have performed manufacturing process of these types of milk, have been carried out by adding proteins and calcium outside the milk itself, sometimes, in the best case, drawn from other milk. This situation means that the organoleptic characteristics of the resulting milk is modified significantly.
A proceeding, by which a milk high in protein and calcium is achieved, while retaining the organoleptic characteristics of normal milk, would be an interesting contribution to the state of the art.